A frame transfer apparatus transferring communication packets or frames, upon receipt of a frame having an unknown destination address copies the received frame and outputs the frame from all of the ports except for the receiving port that received the frame. Such a processing is called a “flooding”.
When a frame transfer apparatus receives a large amount of frames each having an unknown destination address, each of the received frames is copied and output from a plurality of ports, and therefore, congestion occurs in a communication apparatus or a network. As a result, transferring of a frame having a known destination address is affected.
Japanese Laid-Open Patent Publication No. 2010-114724 discloses a technique in which a memory region per unit of port within a forwarding data base (FDB) is dynamically changed depending on communication situation in order to avoid an unnecessary flooding.